Wikipedia
Byarozavik is a Belarusian traditional drink made from birch sap which is harvested from birch trees once a year from March to April. Due to damages caused to the trees because of the popularity of this drink, a licensing system for the collection of sap was introduced in 2008. Birch tree forests, responsibly harvested, actually survive longer than those which are not harvested as the forest is well maintained. The trees can live for as long as 60 years, whether or not they are harvested for birch tree water.
Birch water itself can be used medicinally - externally, or internally. Traditionally it has been viewed as a part of nature's renewable energy cycle, harvested once a year at the break of spring when birch trees awaken after winter dormancy and their sap begins to flow from the root to the top.
It contains many naturally-occurring components beneficial for the human body: healthy sugars, fruit acids, potassium, calcium, phosphorus, magnesium, manganese, zinc, sodium and iron and more. Unique elements include saponin (a nutrient which helps block cholesterol absorption), xylitol (a healthy sugar which promotes dental and skin health) and other cellular-regenerative elements.
Birch tree water is a traditional beverage in Belarus, Ukraine, Russia, Lithuania, Latvia, Estonia, Finland and other parts of Northern Europe as well as parts of Northern China. It has been renowned for centuries not only for its refreshing taste but for its health benefits: traditionally used to help prevent kidney stones, treat ulcers, headaches, and colds - as well as rheumatism, radiculitis and arthritis. Not only is it believed to be immunity-boosting, but also regenerative, flushing out harmful substances and stimulating the metabolism. It contains substances possessing antimicrobial activity (phytoncide) and has been used as a cosmetic face-wash - cleaning, refreshing and renewing the skin.
Entire research institutes were devoted to researching the benefits of this tree in the former Soviet Union. The birch tree water industry collapsed along with the demise of the USSR, and production on a larger scale has only recently restarted.